OBJECTIVES To determine whether prenatal androgen excess during early gestation contributes to the development of ovarian hyperandrogenism in adult female rhesus monkeys, as part of a study investigating the etiology of polycystic ovarian syndrome (PCOS) in women. RESULTS Following intramuscular injection of human recombinant chorionic gonadotropin (hCG), female rhesus monkeys exposed to androgen excess early in gestation exhibited significantly increased serum 17-hydroxyprogeterone levels after 24h and 48h relative to levels immediately prior to hCG injection. In contrast, serum 17-hydroxyprogesterone levels did not change in age and size-matched control females. Serum testosterone levels were higher in prenatally androgenized compared to control females at 48h and 72h following hCG injection. Differential 17-hydroxyprogesterone and testosterone responsiveness of prenatally androgenized compared to control females suggests an ovarian component of hyperandrogenism in female rhesus monkeys exposed to androgen excess prenatally, similar to that found in women with PCOS. FUTURE DIRECTIONS We plan to explore whether ovarian hyperandrogenism in prenatally androgenized females is dependent on elevated circulating LH levels found in adult female rhesus monkeys androgenized prenatally or whether it is the result of prenatal endocrine re-programming of ovarian steroidogenesis. KEY WORDS 17-hydroxyprogesterone, testosterone, ovary, polycystic ovarian syndrome, androgen excess FUNDING NIH grants RR00167 and AG11915, UW Graduate School Research Committee, UW Medical School Committee, UW/Hilldale Faculty/Undergraduate Research Award PUBLICATIONS Abbott D.H., D.A. Dumesic, J.R. Eisner, R.J. Colman and J.W. Kemnitz. 1998. Insights into the development of PCOS from studies of prenatally androgenized female rhesus monkeys. Trends in Endocrinology and Metabolism 9:62-67.